Center finding device



Feb. 15,, 1944. V J, M. lvl-Am z,341,'s75;

Filed Feb. 20, 1943 v Egi- Patented Feb. 15, 1944 i Joseph;MnMalikQToccoa, Ga., assignor toR. G.

Leflfourneau,y Inc., Stockton, Calif., a corpora-4 f tion. of.`` California ApplicationflFebru-ary 20, 1943, Serial No. 476543 f 2 claims. (01. as -iei).

This invention" relates in general to a tool adapted for use in the metal fabricating industries, and in particular the invention is directed to, and it is an object to provide, a unique center finding device.

In the fabrication of metal it is often desirable to have a quick and accurate means of finding and marinng the center of a circular plate or disc so that subsequent operations which require the exact center of the disc to be known, may be performed.

It is therefore a, further object of the present invention to provide a center finding device which is operative to not only locate the exact center of a disc, but also includes a center punch eifective to punch-mark the exact center point, and from which mark subsequent working or cutting operations on the disc can be gauged.

An additional object of this invention is to provide a center finding device which includes a center hub disposed with its axis Vertical, a cen- 4 vter punch slidably supported in said hub, rigid arms radiating from said hub at a substantial angie to each other circumferentially of the hub, and a stop mounted on each of said arms for adjustment lengthwise of the latter.

A further object of the invention is to provide a simple and inexpensive device, and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawing similar -characters of reference indicate corresponding parts in the several views:

,Figure 1 is a plan view of the device in use.

Figure 2 is an enlarged fragmentary cross section online 2-2 of Fig. 1.

Figure 3 is an enlarged fragmentary cross section on line 3-3 of Fig. 1.

Referring now more particularly'to the characters of reference on the drawing, the device comprises a hub I disposed with its axis Vertical, said hub being of substantial longitudinal extent. A center punch 2 is slidably disposed in the hub I with the punch point 3 lowermost. The center punch is enlarged adjacent the point 3 to form a stop shoulder 4 which engages the lower end of the hub and limits relative upward movement of o the center punch.

The upper or head end portion of the center punch projects some distance above the corresponding end of the hub and is formed With a striking head 5 which includes an annular outiii) wardly projecting ange B. A compressionspring` l surrounds the center punch 2 between the flange and the upper end of hub l; said spring being under compression and normally maintaining the center punch retracted, i. e. with the shoulder 4 engaging the lower end of said hub.

Rigid arms 'l are fixed in connection with the hub l at its lower end and radiate therefrom; said arms being disposed at a substantial angle to each other circumferentially of the hub. In the present embcdiment such angle is The radia] arms 'I are of substantial length and each is fitted with a circular stop 8 slidable along the arm but normally held against sliding movement by a thumb screw 9 threaded radially through the stop and seating at its lower end against the arm.

Each stop 8 may include at its inner face a concentric inwardly projecting collar IO of substantially lesser diameter than the stop 8, and whose faces lie in substantially the same horizontai plane as the point of the punch when the latter is retracted. The arms 'l are circular in cross section and the stops 8 and collars Iii are concentric thereto so that for convenience of use the stops can be rotated to varyingly position the screws 9 without interfering with the normal and intended use of said collars. p

If desired the arms may be graduated in inches, as shown at H, reading outwardly from the axis of the center punch.

In use, the device is disposed on top of the disc D whose center is to be located; the point 3 which projects some distance below the arms 'I resting on the upper surface of the disc and the stops 8 engaging the periphery of the disc. The collars 10 ride the face of the disc adjacent the periphery in order to maintain the arms 'l substantially parallel to said face, and the center punch at right angles thereto.

The operater then adjusts the stops 8 until the point 3 of the center punch occupies the same position on the disc when the stops 8 are engaged with the periphery of said disc at a number of circumferentially spaced try points. When the center is thus located, the operater strikes head 5 with a hammer, causing the center punch to be driven downwardly and the point 3 to mark the center of the disc.

If the radius of the disc D is known, then the operater need only set the stops 8 at the corresponding graduation Il on the arms.

With the stops so adjusted they are brought into engagement with the periphery of the disc and the center punching operation carried out.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resortedr to as do not form ardeparture from the spirit of the invention, asfdefined by'the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is: I f

1. In a center finding device which includes center punch, a rigid arm mounted in connection with and radiating from the punch interm'ediate its ends, and a stop unit adjustably mounted on said arm; the arm being ciroular in cross section and said stop unit comprising a stop member mounted on the arm for axial and rotatable adjustment, a supporting element projecting from the stop member radially inwardly of its perimeter toward the punch, said supporting element being circular and concentric to the arm, and a finger screw threaded through the stop member substantially radially of the arm and engaging the latter in stop unit holding relation.

2'. In a center finding device which includes a centervpunch, a rigid arm mounted in connection With and radiating from the punch intermediate itsends, 'andfa stopiunit adjustablyimounted on said arm; the arm being circular in cross section and said stop unit comprising a circular stop member ,r nounted concentrically on the arm for axial and rotatable adjustment, a ciroular supportirig elementfof les'ser dameter than the stop member projecting concentrically from the latter towardthe punch, and a finger screw threaded substantially radiallythrough the stop member and engaging the arm in stop unit holding reiation. V

' JOSEPH-M. MALIK. 

